There are two kernel settings that can help considerably even without using other tools:
swappiness
tells linux kernel how aggressively it should use swap. Quoting the Wikipedia article:
Swappiness is a property for the Linux kernel that changes the balance between swapping out runtime memory, as opposed to dropping pages from the system page cache. Swappiness can be set to values between 0 and 100 inclusive. A low value means the kernel will try to avoid swapping as much as possible where a higher value instead will make the kernel aggressively try to use swap space. The default value is 60, and for most desktop systems, setting it to 100 may affect the overall performance, whereas setting it lower (even 0) may improve interactivity (decreasing response latency.)
vfs_cache_pressure
Quoting from vm.txt:
Controls the tendency of the kernel to reclaim the memory which is used for caching of directory and inode objects.
At the default value of vfs_cache_pressure=100 the kernel will attempt to reclaim dentries and inodes at a "fair" rate with respect to pagecache and swapcache reclaim. Decreasing vfs_cache_pressure causes the kernel to prefer to retain dentry and inode caches. ...
By setting swappiness high (like 100), the kernel moves everything it doesn't need to swap, freeing RAM for caching files. And by setting vfs_cache_pressure lower (let's say to 50, not to 0!), it will favor caching files instead of keeping application data in RAM.
(I work on a large Java project and every time I run it, it took a lot of RAM and flushed the disk cache, so the next time I compiled the project everything was read from disk again. By adjusting these two settings, I manage to keep the sources and compiled output cached in RAM, which speeds the process considerably.)